The present disclosure relates to image forming apparatuses such as copiers, facsimile machines, and printers, which are equipped with a detachable developing device.
For ease of maintenance, a toner container for containing toner (developer), is integrated with a developing device used for an image forming apparatus so as to form a single unit. When the developing device runs out of developer, the whole integrated unit is replaced. However, from an economical viewpoint, the frequent replacement of the developing device is not desirable. Thus, in order to form images on many sheets using developer contained in a single developing device, the amount of developer contained in the developing device needs to be increased. However, with the above-described method, the size of the unit increases as the amount of developer contained in the unit is increased. In order to reduce the size of the developing device, image forming apparatuses wherein the developer is supplied from a toner container separated from the developing device, have been proposed.
With the above-described image forming apparatuses, it is desirable that the toner container or the developing device be separately detachable from the image forming apparatuses for ease of maintenance and replacement of the toner container or the developing device. However, in the situation where the toner container and the developing device are directly connected to each other, the order of attachment and detachment of the toner container and the developing device is restricted depending on the positional relationship of the toner container and the developing device, thereby reducing operability. Furthermore, due to restrictions on the internal layout of the image forming apparatuses, the toner container and the developing device cannot be located adjacent to each other.
In order to avoid the above-described problems, it is known to provide the intermediate hopper between the developer case, such as a toner container, and the developing device. For example, a known image forming apparatus includes a toner transportation device between the toner bottle and the developing device. The toner transportation device has a toner tank unit and a toner transportation pipe. It is also known to provide a service hopper between the toner bottle and the developing device.
With such image forming apparatuses, the developing device or the developer case is separately detachable while leaving the intermediate hopper on the main body side of the image forming apparatus. Furthermore, since the size of the developer case and the developing device can be reduced to a minimum size, the size of the image forming apparatuses can be reduced and the space necessary for the image forming apparatuses can be reduced.
In order to avoid interference of the developing roller (developer carrying body) with the photoconductor drum (image carrying body) when the developing device is attached to or detached from the image forming apparatus main body, the developing device needs to be moved to a position where the developing roller is separated from the photoconductor drum by a specified distance during detachment or attachment of the developing device.
However, as is the case with the above-described image forming apparatuses, when the connection portion of the intermediate hopper, the connection portion being connected to a developer receiving port of the developing device, is secured to the main body side of the image forming apparatus, the positional relationship of the connection portion of the intermediate hopper and the developer receiving port of the developing device may change due to a movement of the developing device. This causes the developer to leak through the connection portion where the developing device and the intermediate hopper are connected to each other.
It is also possible to have a structure in which the intermediate hopper is movable together with the developing device. However, with such a structure: the size of a movement mechanism is increased; a space that allows the intermediate hopper and the developing device to move therethrough is needed; and the positional relationship between the intermediate hopper and the developer case changes. Accordingly, a larger movement structure and greater space are required for the intermediate hopper and the developing device to move together with the developer case in order to prevent a defective connection of the intermediate hopper to the developer case from occurring.